This invention relates to a knock suppression system for an internal combustion engine, and in particular to a knock suppession system capable of completely suppressing knocks at all times even when large variations in factors which generates knocks exist.
In the field of internal combustion engines, the development of knock suppression systems for detecting and suppressing knocks during the engine operation has been energetically made in order to improve the efficiency (fuel consumption) and the output of the engines. While such a knock phenomenon generally occurs in response to variations in numerous factors such as ignition timing, air/fuel ratio, combustion chamber temperature, inlet air temperature, and humidity among the engine operating conditions. In fact, such a knock phenomenon largely depends on the variation of the inlet air temperature and the humidity which, in turn, vary with the seasons of the year. Therefore, the occurrence of knocks alters rhythmically during the period of one year. In other words, the amount of knocks occurring during a short time interval having the same operating conditions is substantially constant so that the frequency of the occurrence and the magnitude of the knocks are substantially constant. Therefore, control signals necessary for the suppression of knocks occurring in the engine for the same operating conditions are not required to be substantially changed during a short time interval.
Hitherto, a knock suppression system based on this fact has been proposed, however, it is incomplete in that corrections can not be carried out in response to the analysis results of specific factors, specifically variations in the above mentioned factors, and therefore, an effective knock suppression has not been realized.
U.S. Pat. No. 4,370,963 discloses the suppression of knocks during a rapid acceleration by rapidly charging an integrator.